Integrated circuits that serve as memory devices or include memory portions are very popular and serve a variety of functions in the electronics world. Resistive random-access memory (RRAM) devices are non-volatile memory type devices formed using semiconductor manufacturing methods. RRAM technology bears some similarities to conductive-bridging RAM (CBRAM) and phase change memory devices.
RRAM devices operate under the principle that a dielectric, which is normally insulating, can be made to conduct through a filament or conduction path formed after the application of a sufficiently high voltage. The conduction path formation can arise from different mechanisms, including defect, metal migration, and other mechanisms. Various different dielectric materials may be used in RRAM devices. Once the filament or conduction path is formed, it may be reset, i.e. broken, resulting in high resistance or set, i.e. re-formed, resulting in lower resistance, by an appropriately applied voltage.
Memory devices are commonly formed using a layout that includes a repeating array of bit cells. One challenge applicable to the formation of an array of RRAM devices is how to manufacture the array using a minimal number of common processing operations. Another challenge applicable to the formation and forming of RRAM devices is how to layout the memory cells and apply a sufficiently high voltage that forms the filament or conduction path in the selected bit cell without adversely affecting the semiconductor devices such as select transistors or other transistors associated with the memory cell.